$re = '/POLYGON\((.*)\)/m';
$str = ' ID geometry
0 1 POLYGON((2.9544435 6.3245124, 2.4098938 6.42657389...))
1 2 POLYGON((3.4324624 6.8735201, 2.4590825 6.23098357...))';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php